// Copyright 2019 The Cockroach Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// This software (KWDB) is licensed under Mulan PSL v2.
// You can use this software according to the terms and conditions of the Mulan PSL v2.
// You may obtain a copy of Mulan PSL v2 at:
//          http://license.coscl.org.cn/MulanPSL2
// THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
// EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
// MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
// See the Mulan PSL v2 for more details.

package log

import "os"

const (
	tracebackNone = iota
	tracebackSingle
	tracebackAll
)

// Obey the GOTRACEBACK environment variable for determining which stacks to
// output during a log.Fatal.
var traceback = func() int {
	switch os.Getenv("GOTRACEBACK") {
	case "none":
		return tracebackNone
	case "single", "":
		return tracebackSingle
	default: // "all", "system", "crash"
		return tracebackAll
	}
}()

// DisableTracebacks turns off tracebacks for log.Fatals. Returns a function
// that sets the traceback settings back to where they were.
// Only intended for use by tests.
func DisableTracebacks() func() {
	oldVal := traceback
	traceback = tracebackNone
	return func() { traceback = oldVal }
}
